A prior art toolbox shown as FIG. 18, the toolbox 50 comprises a lower frame 51 and an upper frame 52. The lower frame 51 has a first locking portion on its rear side and a first locking hole 511 on its front side. The first locking hole 511 is distanced from the first locking portion. The upper frame 52 has a second locking portion on its rear side to latch with the corresponding first locking portion for the upper frame 52 and the lower frame 51 to be joined together. The upper frame 52 also has a second locking hole 521 which is exactly corresponding to the first locking hole 511. The first locking hole 511 and the second locking hole 521 can be buckled by a lock for the lower frame 51 and the upper frame 52 to be tightly locked. Therefore, the toolbox 50 is equipped with anti-theft function. When the lock is removed from the first locking hole 511 and the second locking hole 521, the upper frame 52 is able to be opened against the lower frame 51 for the hand tools to be acquired from the toolbox 50.
However, the anti-theft mechanism of the toolbox 50 still has certain disadvantages. First, the lower frame 51 and the upper frame 52 have the first locking hole 511 and the second locking hole 521 dented on their front sides. the indentations from the first locking hole 511 and the second locking hole 521 make the appearance of the toolbox 50 unsatisfactory, especially facing toward potential buyers while displayed for sale. Second, the indentations the toolbox 50 from the first locking hole 511 and the second locking hole 521 also take up some inner space of the lower frame 51 and the upper frame 52, and therefore the capacity of the toolbox is reduced.